Imagine for a moment that you just invented a time-travel machine.
It is still very basic and does not yet allow you to send yourself or any other living thing. However, you can send non-living things to the past or the future.
Discuss: What one thing would you send to the past or future and who would you send it to?
Discuss: Why would you send that item?
Discuss: If you could receive one thing from the past or the future, what would it be and from whom?